There are a wide variety of image detectors, such as visible image detectors, infrared image detectors, or other types of image detectors that may be provided in an image detector array for capturing an image. As an example, a plurality of photodiodes may be provided in an image detector array, to detect electromagnetic radiation at desired wavelengths. Such detectors may be connected to or part of unit cells in a read out integrated circuit (ROIC) which capture image data in response to the detected radiation and then communicate that image data to external electronics. The combination of a detector array with an ROIC is known either as a focal plane array (FPA) or an image sensor.
Each ROIC unit cell commonly includes one or more regions for storing electric charges generated by an associated detector. As image detector arrays trend toward including more and more detectors in a given area, the area of each unit cell is correspondingly decreased. This decrease in unit cell area leads to a decrease in the total capacitance available for charge storage for each image detector. This decrease in capacitance can be problematic, particularly in detector technologies that have relatively large dark currents. Accordingly, there is a need in the art for improved ROIC architectures to provide increased charge storage capabilities.